Stark broadening of high principal quantum number hydrogen Balmer lines in low-density laboratory plasmas

We present results for Stark broadening of high principal quantum number (up to $n=15$) Balmer lines, using an analytical (the “standard theory”) approach and two independently developed computer simulation methods. The line shapes are calculated for several sets of plasma parameters, applicable to radio-frequency discharge $(N_e\approx {10}^{13}{\mathrm{cm}}^{-3})$ and magnetic fusion $(N_e\approx {10}^{15}{\mathrm{cm}}^{-3})$ experiments. Comparisons of the calculated line profiles to the experimental data show a very good agreement. Density and temperature dependences of the linewidths, as well as relative contributions of different Stark-broadening mechanisms, are analyzed. It is seen that the standard theory of line broadening is sufficiently accurate for the entire set of plasma conditions and spectral transitions considered here, while an alternative theory (“advanced generalized theory”) is shown to be inadequate for the higher-density region. A discussion of possible reasons for this disagreement is given.